DAC resolution

[Paul Schreiber]

Sigh.

The *quick* version is:

a) if you are controlling decent VCOs, say 4-6 at a time
b) you have "musical" ears and can hear 0.2% pitch deviation
(this was documented 25 ears ago in JASA)

Then your VCO DAC needs to have about 300uV per step.

If an 8-bit DAC is spanning 1 volt, the dac has 1/2LSB accuracy.

So 1v/256 steps = 3.9mv and the DAC can only hit that +-1.95mv.

This is a ~2% error (1.95mv/83.3mv). This does NOT include errors in the
"octave switching" mux used or the Vref drift.

OK?

If you are controlling a monosynth and playing fast techno and not beating
VCOs in a slow string pad, there is a good possibility you will not NOTICE
the error. You may get a "good" DAC-08 that is like 1/8th LSB error by luck.
But the proper engineering solution is not to use one.

I mean, go to www.maxim-ic.com and look at the 12-bit parts. FREE samples!
Sheesh!

Paul Schreiber